By: LaShanale Wallace. Introduction: What is Autophagy? Objective Specific examples Conclusion.

By: LaShanale Wallace

Introduction: What is Autophagy?

Objective

Specific examples

Conclusion

A vital cellular process by which intracellular components are degraded within the lysosome

An essential for survival, differentiation, development, and homeostasis

Is to ensure cell survival through unfavorable situations ex….

Nutrient absenceGrowth factor withdrawAbundant amount of toxic proteinsDefected organells

The Roles of Autophagy in life and disease

Focusing on the dual roles of autophagy

Specific examples are…

1. Its role as cytoprotective autophagy

2. Its role in skeletal muscle and aging

3. And its role in pancreatic cancer

Purpose Investigate expression pattern and

sublocalization of caspase 8 in TRAIL mediated autophagy

Expression of caspase 8 in shift from autophagy to apoptosis

Materials HCT colon carcinoma cells treated with

TRAIL

Method Quantitative

image cytometry,

Confocal microscopy assay.

Immunoblot

Inhibition of autophagy induces caspase 8 activity

Cleaved caspase 8 localizes to autophagosome, inhibiting apoptosis

This study provides evidence for regulation of caspase 8 activity through autophagy

Capase 8 provides a cross talk mechanism between autophagy and apoptosis

PurposeDoes autophagy in

skeletal muscle change with age?

Does exercise and calorie restriction have an effect on autophagy?

Materials Male Fisher RatsAd libthium dietFour groups: Y,O,

OCR, and OCREXFast twitch muscle

tissue

Results Autophagy decreases with age.

Calorie restriction increased autophagy response

Exercise had no significant effect

Age is associated with lower levels of autophagy. This leads to increased cellular damage and apoptosis causing muscle loss.

Mild calorie restricted diets increased

autophagy in older rats, protecting muscle from cell damage and death

PurposeDemonstrate that pancreatic cancers are dependent on autophagy for growth

Pancreatic tumor cells are sensitive to autophagy inhibition

Pancreatic ductal adenocarcinoma cells(PDAC)

Control cell lines MCF7, H460, AND HPDE

GFP-LC3 assay Chloroquine

inhibitor

Assay determined degree of autophagy

Immunochemistry monitored LC3 expression during tumor progression

CQ Treatment

PDAC has high levels of basal autophagy Autophagy is upregulated during tumor

progression PDAC is sensitive to CQ treatment PDAC Mice treated with CQ live longer

Since PDAC is dependent on autophagy, this provides a potential target for therapeutic intervention

Since chloroquine is already used as a anti-malaria therapeutic, clinical trials using drugs targeting autophagy inhibition are strongly suggested for pancreatic cancer

Functions of autophagy can be beneficial are harmful

Its role to promote cell survival…. Is beneficial in life processes such as

aging Harmful in diseases like pancreatic cancer

With knowledge researchers can create therapeutics and either inhibit or increase autophagy pathways for more favorable outcomes.

Dr. Muganda MARC Program Dr. White Mrs. Petty Mrs. Sindy Martin

1. Wohlgemuth, S. E., Seo, A. Y., Marzetti, E., Lees, H. A., and Leeuwenburgh, C. Skeletal muscle autophagy and apoptosis during aging: effects of calorie restriction and life-long exercise. Experimental Gerontology 2010; 45: 138-148.

2. Young M, T. Y., Khan O, Park S, Hori T, Yun J, Amin S, Hu C, Zhang J, Kester M, and Wang H. Autophagosomal membrane serves as a platform for an intracellular death-inducing signaling complex (iDISC)-mediated caspase-8 activation and apoptosis. The Journal of Biological Chemistry. 2012; 287: 12455-12468.

3. Rosenfeldt MT, Ryan KM. The multiple roles of autophagy in cancer. Carcinogenesis. 2011; 32(7): 955-963.

4. http://tp-apg.genes.nig.ac.jp/autophagy/5. http://www.wormbook.org/chapters/www_autophagy/

autophagy.html6. http://www.invitrogen.com/site/us/en/home/References/

Molecular-Probes-The-Handbook/Assays-for-Cell-Viability-Proliferation-and-Function/Assays-for-Apoptosis.html#head7

7. http://beaker.sanfordburnham.org/2011/09/autophagy-101/